Vehicle door window regulators having a lift arm operatively connected to a motor or to a manual crank and a balance arm pivotally connected to the lift arm are well known in the art. An example of such a design is shown in U.S. Pat. No. 2,010,075 to Graf. The regulator includes a crossed lever arrangement wherein one end of a substantially straight lift lever is operated to pivot about a fixed point on the door with the other end of the lever having a roller or stud slidably engaging a horizontal channel connected to the bottom of the window. A substantially straight balance lever is pivotally connected at an intermediate point along its length to an intermediate point along the length of the lift lever. A roller at one end of the balance lever slidably engages the horizontal channel connected to the window while a second roller at the other end of the balance lever slidably engages a horizontal channel attached to the door.
While the foregoing arrangement has worked well with windows having vertical edges, current vehicle designs incorporate B-pillars (i.e., the door pillars at the trailing edge of the door window) which are rearwardly angled away from the vertical. For an angled B-pillar design, the window must have angled edges and move along an inclined path as it is being raised or lowered. The mechanism forces, i.e. the forces exerted on the window by the window regulator, of the described prior art regulator are generally along a vertical direction. Consequently, an unmodified regulator of this type would not be ideally suited for use in an automobile door having an angled B-pillar, as it would undesirably exert forces having a component perpendicular to the B-pillar, thereby subjecting the glass-run channel and weather-stripping along the B-pillar to undue forces. In addition to the weatherstripping, other components such as arm catchers, regulator arms and the regulator motor are deleteriously affected by the undesirable forces exerted on the B-pillar when the direction of the mechanism force of the regulator is not substantially parallel with the window opening edge of the B-pillar.
Additionally, contemporary vehicle designs incorporate side window glass panes which are curved about an axis of curvature generally parallel to the normal direction of forward motion of the vehicle and, more importantly, transverse to the direction of travel of the glass when the glass pane is raised or lowered. This curvature also induces undue stresses on the glass-run channel weatherstrips and regulator components when the mechanism forces are directed along a substantially vertical straight line as with the simple crossed lever arrangement. Various modifications have been made to the described crossed lever design; however, none of these specifically address or solve the problem of how to raise and lower a window, particularly a curved window, along an inclined path without exerting undesirable forces on the weatherstripping and other components.